Béla IV was the King of Hungary from 1235 to 1270. He is known for his efforts to rebuild the country after the devastating Mongol invasion in 1241. Béla implemented various reforms to strengthen the economy and improve the defense of his kingdom. During his reign, Béla IV also promoted the settlement of German and Slavic peoples in Hungary, which contributed to the cultural diversity of the region. He established several towns and encouraged trade, helping to restore stability and prosperity in the aftermath of the invasion.